The average size for an adult female is just under 3 m (9.8 ft), while the adult male usually falls between 4-4.5 m (13-14.7 ft). Legs of American alligators are characteristically short, though capable of carrying the animal at a gallop. The front legs have 5 toes while the back legs have only 4. Nostrils at the end of the snout allow for breathing while the alligator is fully submerged below the water. During hibernation, alligators keep these nostrils just above the water's surface, allowing the top part of the body to freeze in ice. They have an "armored" body with a muscular flat tail, used in propelling the animal forward while swimming. The skin on their back is armored with embedded bony plates called osteoderms or scutes. Adults have an olive brown or black color with a creamy white underside. The young can be distinguished from adults because they have bright yellow stripes on their tails. Eye color of American alligators is generally silverish (Britton 1999; Ross 1989).